In the quest to make Imax more commercial and less institutional--limiting it to making films for educational purposes and science centers--CEO Richard Gelfond figured out how to suck the costs out of the Imax process and retrofit it into regular theaters. They did it, he told a Fortune forum, by using proprietary algorithms they had worked on over a long period of time, and by using existing technology to lower to costs of turning existing Hollywood films into Imax films. It used to cost $30,000 to screen one Imax film, and now it costs about $150.

Gelfond also changed the Imax business model--not by reinventing it but simply by using a different existing model. Instead of selling theaters Imax equipment, the company gave it to them free in exchange for showing more Imax movies--which consumers are willing to pay a higher price for because it gives them a more exciting and richer film-going experience.

Innovation is often about riffing off what exists and filling in the gaps.

The best innovations are often not based on something unknown or yet to be discovered, but are grounded in an understanding of the past, of ingrained cultural habits and behavior patterns, and in making judgments and informed decisions based on that knowledge. In other words, you pull the red threads of what you already know and weave them together into a new take on an old theme. That’s what Imax did when it understood that people liked the Imax experience in science centers, and would likely enjoy it even more when they would experience Imax while watching their favorite Hollywood movies.

While the fastest, most profitable innovation opportunities are likely right in front of you, they often go unnoticed. Chris Zook’s research at Bain & Company demonstrates how pivotal looking under your own hood can be. He found that 9 out of 10 companies that successfully renewed themselves built that renewal on hidden and existing assets. It’s all about seeing the potential in what already exists, but which is taken for granted or unleveraged.

Look at all your resources with fresh eyes.

Review false starts, old tools, undeveloped prototypes, notes, gadgets, formulas, recipes, and past research and reports. Who else might that information interest? There may be a different audience than originally intended. How can the material be combined or tweaked in a new way to appeal to a new audiences?

Dove did it when it reinvented its line of soap--which it strongly positioned for women. They turned their eyes to men. In 2010, Dove launched Dove Men+Care, a new line of male personal-care products. The company understood that its existing brand, already targeted narrowly at women, would not be of interest to male customers. But they also knew that the men’s personal care market had expanded and was quite different than it was in 2000. They used existing products but tweaked them for a male market, with "manly" packaging, color schemes, and graphics. The line is a hit.

Don’t abandon good technology because it doesn't work the way you thought it would.

Excel Dryer in East Longmeadow, Massachusetts, makes one of the most popular high-quality models of air hand dryers for public restrooms. Denis Gagnon bought the company in the 1990s, and discovered a problem--people hated using the product, he told NPR.

Anyone who has been in a public bathroom with a air dryer knows that that 35-40 seconds it takes the machines to dry your hands feels like an eternity. That’s why a lot of us give up and leave with our hands still damp. Looking for a way to improve the air-drying experience, Gagnon found Invent Resources, run by four scientists who had retired from their day jobs as physicists, were offering their expertise to companies who wanted to build better products.

One technology that Invent Resources had come up with was for a super fast hairdryer, which failed to impress industry leader Conair. Instead of abandoning the technology, Invent Resource scientists applied to the hand air dryer--and Gagnon climbed aboard because the air dryer cut drying time down to 12 seconds. It makes more noise than conventional had dryers, but it really works, so who cares? It’s also a hit for Excel; sales for the company have gone up more than 10 percent every year.

Go back to basics and expand on that.

Too often a business looks at its market change and thinks, oh, it has outgrown my product, there’s nothing I can do. That almost happened to the Denmark-based international toy powerhouse LEGO. In 2003 and 2004, sales were so bad that the company almost liquidated. But a new CEO, Jørgen Vig Knudstorp, recognized that it wasn’t LEGO itself that had become obsolete, it was the fact that LEGO's main assets--creativity and personalized building--weren't in sync with its shifting audience. The toy could keep its core principles of building and creativity, but in a way that appealed to a more mature buyer. Vig Knudstorp saw that children were growing up and becoming more sophisticated at a younger age, as were the retail channels that sold the toys (such as Toys ‘R Us and Walmart).

One of the things that Vig Knudstorp did was to go back and look at its early models and realized that during years of major expansion, the company had gone from creating about 2000 LEGO pieces to more than 10,000 pieces--but that variety wasn’t really creating added value for the consumer. LEGO cut the number of pieces it made in half, and designers rediscovered what LEGO was all about--personal creativity and invention. But now with a more limited but versatile set of pieces. Profits went up. The company also used existing assets and expanded into movie tie-ins and theme parks--both appeal to a more sophisticated youngster.

If big companies like Imax, Dove, and LEGO can innovate based on existing assets, and if even a small manufacturer of a niche item like a hand dryer can succeed by looking at existing but underused technology, then you can do it too. All you have to do is take another look at what you already have going for you.

The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.